1969 Baird 8724

14 963

Follow this sets restoration from dumped empty cabinet to full working television

1969 Baird 8724 1

1969 Baird 8724

BRC 3000 Chassis

Model: 8724


System: 625 Line

Original List Price : £000.00 ( to be ascertained)

Valves: None, all transistor

General Info:

This 25″ Baird 8724 is quite a rarity, it used the first generation Thorn 3000 single standard chassis. As far as I know there are only two other survivors known to the vintage communities, of course if you know different please leave a comment below.

This is what it should look like, however you will see the one I found was shall we say, a little neglected!

Baird 8724


The one I located was just a cabinet, I bought it from a nice fella in London who found it on the street, dumped with the rubbish. He took pity on it and gave it a home and briefly toyed with the idea of turning it into a fish tank.

Thankfully fate intervened in the form of a pregnant wife and he was forced to sell it on, which leads us back to fate and it coming to me. I had hoped to find one of these Baird sets but as I say they are so rare it was highly unlikely to ever happen. So when a chance of this came up regardless of condition I snapped it up.

So the condition? Well its a mammoth project, it is just an empty cabinet. The chassis is missing along with the CRT having had its neck snapped off. The scan coils gone as well as convergence yoke, blue lateral, chassis mount cross members all the internal panels such as IF, decoder, video, frame, line and power etc. The back panel is missing and the crt mask is damaged. What remained from the original set was the tuner and aerial input, on off, colour brightness, volume controls. the speaker. Well that’s a positive I suppose.

The Baird As Found

Looks good you think? all there…. Well all is not as it would seem


It had been completely gutted, and the CRT necked. All I was left with was the tuner, controls and speaker.


First thing to do is locate a replacement CRT as without this the project is a non starter. As luck would have it, I was put in contact with an Ex Trade engineer who had an unused re-gunned Mazda A63 200X.

A call to another Ex engineer located a BRC 3500 chassis frame with harness and over the next few weeks all the panels to rebuild the set were sourced some 3000 some 3500.

I set about making the missing horizontal chassis support rail, this fixes the vertical supports rail. Once installed the rail and runners installed were added. Picture shows 3500 chassis frame sitting on the support rails.

bd4 bd5 bd6 bd7 bd8



All the missing boards have been sourced, they came from various sources and sets, no doubt some components will need replacing. I assembled them on the 3500 frame. Made a track repair to the video board a C227 had been replaced with a monster 2uF 350V tacked on the underside. This resulted in the track breaking away, I removed the large cap, replaced it with the correct 2.2uF 63V on the component side then repaired the broken track underneath with some bridging wire.


Replacement CRT fitted, wired up the Yoke, I noticed on the PSU the 30v Zener in the stabilising circuit is missing along with C609 a 400uF 63V electrolytic. I didn’ have any suitable zeners in stock so ordered up a 1N5353 5W. Also found on the Convergence board the A1 switches have been removed and are shorted out, these need replacing. Also need to sort out the missing tuner plugs, sort out the missing degauss shield plug, check the LOPT is wired for the right kV,and do some final checks, mainly wiring checks. The blue lateral assembly had damage to one end, a lug which had a hair wire and two other was broken. I’ve made repairs but I’m not sure how good it will be until we have something on screen.

bd12 bd13 bd14 bd15 bd16 bd17 bd18 bd19 bd20


PSU module has had the electrolytics replaced and the 30V zener. Power applied, the set trips, found the Chopper transistor had failed. Installed a new one, same scanario, Chopper is OK. Tried the PSU in another sets 3000 chassis, same scenario, trips. PSU back in the Baird, removed 6 pin plug from underneath, still trips. Found dry joint on the 300V chopper collector and a Burnt and low resistor, still tripping.
Next is to isolate the collector and try further component tests to isolate the cause of the tripping.


Tracked the tripping issue. Once W621 and SCR957 was removed the tripping ceased. The SCR was tested on a bench supply and at 1.5V it would latch, when tested at 30V it would intermittently latch so appears to be failing under load. A new SCR was fitted and as a precaution the 72V zener W617 BZX61-C72 was also replaced.

Powered the PSU up still with the board isolated from the LTB and the chopper collector drive removed, the tripping has stopped. Now to reconnect the chopper, test and the LTB test, hopefully the tripping will not reappear.

Minor Update:

Reconnected the feed to the chopper VT604 removed F603 and connected a dummy load to L603. Powered on set did not trip however the dummy load lit up very bright, 158V across L603 when it should be 60v. Investigation continues


Tracked the issue down to faulty new components, namely the new chopper transistors. Installed an old chassis-pull R2010B and voltages return to normal.

Now the PSU seems stable I hooked up all the interconnects and F603, powered the set and I have first sound. No first light but its a step in the right direction. The 60v rail is low at 27.8v and no EHT.


R907 was very hot indication that excessive current is being drawn. Replaced the Line output transistor but this did not resolve the issue. Removed the EHT transformer and performed a ring test, this revealed a very poor ring indicating shorted turns.

As a matter of precaution the EHT and line output transformers were replaced along with the tripler. Ring trace on the new EHT TX reveals a good ring.





After replacing the TX’s It was found that I had on wire wrong on T504 to T503, once rectified I had full 60V rail and EHT. Video board and sound produced nothing, a squirt of cleaner in A1 restore this switch and first light.


Next Test was to prove the I.F. board and tuner, that seems to be ok




Lots to sort out, A1 controls are quite high, I need to find some purity rings, sort the convergence, perform EHT set up. All the boards except PSU and LTB need servicing many awful caps are present.


Results after Setting EHT, Grid bias, Porch Bias, Clamp pulese level, Grey scale adjustment. Below is the grey scale test card. Looking much better now. However I still need to do Pre-set Brightness and Beam Limiter.
One outstanding fault is I don’t have any colour whatsoever coming out of the chroma/decoder. Out of interest I installed a known working 3000 chroma board into the Baird, this then gave me colour. This proves the Baird chroma board has the final remaining fault to track down.

The investigation will start with disbaling the colour killer and hopefully the results on screen will lead me to the true fault. Below is the picture of the Baird showing a colour picture (using another sets chroma board) for the first time, ah it could be 1969 all over again.



Fault finding on the Baird chroma board revealed an OC diode in the blanking circuit, namely W316. It would appear on even closer inspection today, W317 had also gone O/C, so both blanking diodes had failed. These were replaced with NOS OA91 diodes. This resulted in colour being restored, I’ve not done any setting up so you’re seeing what I saw when it came on but that’s the Baird now running with all its own panels.





A few more faults came to light after a soak test with the beam limiter, frame board and tuner. The tuners mechanical plastic stop had perished and were replaced as per the guide here. The other faults were addressed along with a convergence.





Finally a solution to the missing back cover. Making one would have been difficult but not impossible, however I decided to wait until something to turn up from a scrap set. The time came when a Dual Standard Korting cabinet appeared on E-bay. I contacted the owner and suggested that if the cabinet did not sell I would make a generous offer for just the rear cover. The cabinet did not sell and subsequently I obtained the cover.
This now forms the greater part of the back, all I need to do is adapt a bottom straight cover and small left side cover.





The Baird now running in the display room.

Receiving 2 UHF channels from my home analogue distribution system BBC1 showing Test card F with test card music via the IMOGen generator and on ITV via a DVD, Crossroads.




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9 years ago

There was a time, not so long ago, when TV set’s similar to this were discarded left right and centre. Yesterday’s rubbish is today’s treasure.

Oh to have had the insight and space to have kept some….
Thank God there are people like the founder of this web-site who are restoring what we have left.

9 years ago

Thanks to this web site and Chris’ amazing example, I am fast catching the early colour TV bug. All I can say is I am most impressed at what has been achieved here, and not a little envious…

Paul Remfry
Paul Remfry
8 years ago

Thanks for posting this. I repaired many 3500s in my day and this brought back many good memories – I could actually smell the things again!!!
I had a Baird or two like this one pass through my hands too – but they were hybrids with PY500s (I think they were) as one bit me once! Went right through the side of my finger and down to the bone with a lovely burning flesh smell – gave me quite a jump I can tell you!

michael o' brien
8 years ago

Loved your pics of this TV’s restoration,I rented one of these from Radio rentals in Derby in the 70’s,i absolutely loved it ,it was a real statement piece.I remember it cost £8.50 per month to rent,I thought it was worth every penny,it even looked impressive when closed.I moved to Ireland in the late 70’s and was really loathe to have to send it back,however I can console myself(no pun intended!)that I have a great photograph of it in my living room,standing next to my Grundig ‘Balmoral’ radiogram,which I still have and is much treasured. Thanks for posting this,it was great to see it. Mike.

8 years ago

We have the later 3500 version baird 8736 (looks very similar 26″ with tambour doors) down here in sunny Cornwall. I have made a start on her the main electrolytic is in a very sorry state but thankfully the set is very original. It was to big for its owners to take to the tip !! so they just plonked a new set on top.

phil price
phil price
6 years ago

I have repaired thousands of these models being a Radio Rentals engineer for 25 years. 10 to 12 calls a day no sat nav, no phone, time calls , no backup Loved it. Did you change the 1.5 ohm wire wound resistor on the beam limiter panel. Gives limited brightness range and is a very common fault. We scrapped thousands of these . Oh if only I had saved a few.
Phil Price

Howard Brereton
Howard Brereton
6 years ago

Great post and very nostalgic . I was engineer for Rumbelows then Radio Rentals which became Thorn Homeserve then Box Clever ( don’t ask !) . Redundant in 1995 after almost 20 years man and boy.

Anyone else used to NRCL ( no reply card left ) after 5 calls at 2pm then go home? 🙂

Memories…. Ford Escort 1100 … don’t forget to fit your side panels

Reply to  Howard Brereton
6 years ago

Ah the BRC3500 and a great restoration story. I cut my teeth on those and the BRC 1500. I attended a Thorn-EMI course for these as a new recruit in London for DER in the early 70’s. Then moved on to RR and left in the 90’s. As an electronics hobbyist, I even got paid for what I loved doing. In my mid 60’s now and I still have those original circuits with faults marked out in pen.
Where are all the engineers now, I wonder.

6 years ago

I’m posting as a child of the 60’s with very fond memories of this TV. We got one in I think 1969 instead of a holiday that year and I have to say I think it was very well worth it. I remember very well the Saturday it turned up, it needed a BBC 2 Ariel to make it work. The main thing of note was it’s size, it was like a cinema in our living room and in colour too! It was very well looked after, the doors were closed every night and my mum kept it well polished. It’s really nice to know others hold it in such esteem and take the trouble to keep it going, thank you.

Marcus 3700
5 years ago

Hi Chris,
Well certainly a tale of rags to riches regarding this set, and what a transformation from the first picture to the last.

5 years ago

Hello Chris

Fantastic restoration! It takes real dedication to keep going faced with a set in that condition.

I worked for Thorn in the mid 80s (Multibroadcast and later Thorn Homeserve. We never really saw these then but plenty of 8000, 9000, 9600 and even the occasional 4000! (lots of thick film resistors in there!) Export mainly but we had a few on rental.

I repaired my first 3500 ( a large 26″) when I was 15 in 1978! It was a friend of my dads and he rashly said his lad could fix it! I quite a nasty fault introduction to these sets. The tripler had failed, but they had continued to use it for sound only until it tripped the cut out.

Long story short, both line and EHT Transformers had failed, the line o/p Transistor, and a capacitor (cannot remember what it was now but it was S/C). Think there was a diode too had expired. Ordered all the parts from Sendz components and Manor supplies from the TV magazine, and got it working. I did have a manual so that helped!

Also my Uncle was a ex TV engineer and gave some advice too. The only other fault it had was purple vertical bars and my uncle told me to change 3 x 2.2uF capacitor on the RGB panel (cannot remember the component numbers now but it cured the fault).. I encountered many more 3000/3500 in the later years, but where are they now. not seen one for maybe 30 years.. you must have them all Chris!


2 years ago

Hey Crusty,
Great restoration, I particularly liked the wood frame rails, as I am currently fabricating VCR doors/flaps for my collection… necessity is the mother of invention they say.
Not sure what the original chassis would have been…. That model was the first colour picture on a TV that I ever saw, maybe 1969? My Dad was in the repair trade and it was the first TV I ever saw a colour picture on, colour test card then Take Your Pick hosted by Michael Miles. At the time I was hugely impressed! Your set has come up beautifully, a real time warp for me!!
Thanks for the pics!!!

2 years ago

Did anyone else start humming the Eastenders theme tune when they saw the PCB wire bridge repair?

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